These putative effects can be taken in context of a wide range of cardiovascular phenomena regulated by the endocannabinoid system and an overall role of cannabis in causing decreased peripheral resistance and increased cardiac output, which potentially could pose a threat to those with cardiovascular disease.
Although global abnormalities in white matter and grey matter are not associated with cannabis abuse, reduced hippocampal volume is consistently found.
- in India and Nepal since the Vedic period dating back to approximately 1500 BCE, but perhaps as far back as 2000 BCE.
There are several references in Greek mythology to a powerful drug that eliminated anguish and sorrow.
Cannabis was ranked 11th in dependence, 17th in physical harm, and 10th in social harm.
Acute effects may include anxiety and panic, impaired attention, and memory (while intoxicated), an increased risk of psychotic symptoms, and possibly an increased risk of accidents if a person drives a motor vehicle while intoxicated.
A 2015 meta analysis found that, although a longer period of abstinence was associated with smaller magnitudes of impairment, both retrospective and prospective memory were impaired in cannabis users.
In 2013, between 128 and 232 million people used cannabis (2.7% to 4.9% of the global population between the ages of 15 and 65).In some cases, cannabis can lead to dissociative states such as depersonalization Aside from a subjective change in perception and mood, the most common short-term physical and neurological effects include increased heart rate, increased appetite and consumption of food, lowered blood pressure, impairment of short-term and working memory, psychomotor coordination, and concentration.Some users may experience an episode of acute psychosis, which usually abates after six hours, but in rare instances, heavy users may find the symptoms continuing for many days.A 2012 meta analyses found that deficits in most domains of cognition persisted beyond the acute period of intoxication, but was not evident in studies where subjects were abstinent for more than 25 days.One review found three prospective cohort studies that examined the relationship between self reported cannabis use and intelligence quotient (IQ).